05/17/2019 at 19:26 •
#For wearable projects 18650 lithium cells tend to be too large. I see tons of project using flat lithium packs instead or just non-rechargeable alkaline batteries. I don't like flat pack lithium batteries since they are easy to puncture and with a hard case they are almost as large as 18650s.
There is a good alternative which is a good compromise between size, sturdiness and capacity: The cylindrical 14500 lithium battery. 14500 is essentially the same size as an AA alkaline battery. From what I can gather there is pretty much only one company which sells them in quantities in the US: Tenergy. These batteries have a 800mAh capacity which is pretty good for their size and they are fairly sturdy while being small enough. I buy them in batches of 100, at $3.69 a pop. Also, when you order 100 you get them in their original neat packaging. Product page: http://www.tenergy.com/30001 Tenergy has an online store where you can buy direct: https://power.tenergy.com/tenergy-li-ion-14500-cylindrical-3-7v-800mah-flat-top-rechargeable-battery-ul-listed/ They are based in Fremont, CA. Reputable company from what I can gather, never had an issue with them.
Highly recommended for portable projects where 18650s are just too large.
05/17/2019 at 19:06 •
Before we start on a project which needs a lot of parts we need to make sure we can acquire them. So, I bought all my LEDs before even starting to design the PCB.
Like last year I wanted to go with APA102-2020s since they survive pretty much everything you throw at them. To give you some context, I commonly deal with WS2812/SK6812 modules for other projects and in my experience these modules have a huge downside: The bonding wires inside these don't survive being reflowed twice which is a no-go for a double sided PCB. The APA102-2020 module on the other hand is completely epoxied in, without loose bond wires. But they have a huge downside too: They are a PITA to reflow properly without bridging. The pads on the bottom are just too damn small:
But we have a new contender on the block, the WS2812C-2020. Like the APA102-2020 they are completely epoxied in and survive several reflows easily and more importantly they are super easy to even solder by hand, despite their small 2mm x 2mm size.